There are a lot of motor shaft adaptation system techniques being disclosed, such as U.S. Pat. No. 6,328,655 B1 and U.S. Pat. No. 5,501,117. The motor shaft adaptation system technique has been widely applied in the door machine mechanism for driving the door, but the safety was easily ignored.
The conventional door, such as the rolling door with vertical lifting and descending, all have very serious design criteria based on the safety consideration. In ideal case, the door should not have any possibility of danger caused by factitious or non-factitious factors under any operational conditions. The industry has the common goal to improve the product toward this target, so as to reduce the danger for door to the minimum.
In the door system, the reel mechanism, having the lowest failure probability compared to other mechanisms, belongs to the mechanism having better safety. Thus, the person skilled in the art usually pays attention to the improvement on the mechanism with higher failure probability, such as control mechanism, and often ignores the potential danger of the reel mechanism. However, it is appreciated by the person skilled in the art that, although the reel mechanism has better safety, it still could not prevent the abrasion problem between gear sets after long-term usage. Once the gears of the reel mechanism have been worn to a certain critical level, in the case which is not detected by an effective detection mechanism, there will be a great danger of the rolling door to stall and fall down.